Teaching Mathematics to Chemistry Students with Symbolic ComputationJ. F. Ogilvie and M. B. MonaganThe authors explain how the use of mathematical software improves the teaching and understanding of mathematics to and by chemistry students while greatly expanding their abilities to solve realistic chemical problems.Ogilvie, J. F.; Monagan, M. B. J. Chem. Educ.2007, 84, 889.

Chemometrics |

Computational Chemistry |

Fourier Transform Techniques |

Mathematics / Symbolic Mathematics |

Nomenclature / Units / Symbols

Sudoku Puzzles for First-Year Organic Chemistry StudentsAlice L. Perez and G. LamoureuxSudoku puzzles are used to help the students learn the correspondence between the names of amino acids, their abbreviations, and codes; and the correspondence between the names of functional groups, their structures, and abbreviations.Perez, Alice L.; Lamoureux, G. J. Chem. Educ.2007, 84, 614.

Concentration Scales for Sugar SolutionsDavid W. BallExamines several special scales used to indicate the concentration of sugar solutions and their application to industry.Ball, David W. J. Chem. Educ.2006, 83, 1489.

Nomenclature / Units / Symbols |

Food Science |

Solutions / Solvents

Classifying Matter: A Physical Model Using Paper ClipsBob Blake, Lynn Hogue, and Jerry L. SarquisBy using colored paper clips, students can represent pure substances, mixtures, elements, and compounds and then discuss their similarities and differences. This model is advantageous for the beginning student who would not know enough about the detailed composition of simple materials like milk, brass, sand, and air to classify them properly.Blake, Bob; Hogue, Lynn; Sarquis, Jerry L. J. Chem. Educ.2006, 83, 1317.

Molecular Properties / Structure |

Nomenclature / Units / Symbols |

Solids |

Student-Centered Learning

More on the Nature of ResonanceRobert C. KerberThe author continues to find the use of delocalization preferable to resonance. Kerber, Robert C. . J. Chem. Educ.2006, 83, 1291.

Aromatic Compounds |

Covalent Bonding |

Molecular Properties / Structure |

Resonance Theory |

Nomenclature / Units / Symbols

More on the Nature of ResonanceWilliam B. JensenSupplements a recent article on the interpretation of resonance theory with three additional observationsone historical and two conceptual.Jensen, William B. J. Chem. Educ.2006, 83, 1290.

Octachem Model: Organic Chemistry Nomenclature CompanionJoaquin PalaciosThe Octachem model is an educational physical model designed to guide students in the identification, classification, and naming of the chemical structures of organic compounds. In this article the basic concepts of Octachem model are presented, and the physical model and contents are described.Palacios, Joaquin. J. Chem. Educ.2006, 83, 890.

The Rainbow Wheel and Rainbow Matrix: Two Effective Tools for Learning Ionic NomenclatureJoseph S. Chimeno, Gary P Wulfsberg, Michael J. Sanger, and Tammy J. MeltonThis study compared the learning of ionic nomenclature by three different methods, one traditional and the other two using game formats. The game formats were found to be more effective in helping students develop a working knowledge of chemical nomenclature.Chimeno, Joseph S.; Wulfsberg, Gary P.; Sanger, Michael J.; Melton, Tammy J. J. Chem. Educ.2006, 83, 651.

Nomenclature Made Practical: Student Discovery of the Nomenclature RulesMichael C. Wirtz, Joan Kaufmann, and Gary HawleyPresents a method to teach chemical nomenclature to students in an introductory chemistry course that utilizes the discovery-learning model. Inorganic compounds are grouped into four categories and introduced through separate activities interspersed throughout the first semester to provide context and avoid confronting the student with all of the nomenclature rules at once. Wirtz, Michael C.; Kaufmann, Joan; Hawley, Gary. J. Chem. Educ.2006, 83, 595.

Nomenclature / Units / Symbols |

Nonmetals |

Student-Centered Learning

Acrostic Puzzles in the ClassroomDorothy SwainAcrostic puzzles are an effective vehicle to expose students to the history and philosophy of science without lecturing.Swain, Dorothy. J. Chem. Educ.2006, 83, 589.

Atomic Properties / Structure |

Enrichment / Review Materials |

Nomenclature / Units / Symbols |

Nonmajor Courses |

Periodicity / Periodic Table

If It's Resonance, What Is Resonating?Robert C. KerberThis article reviews the origin of the terminology associated with the use of more than one Lewis-type structure to describe delocalized bonding in molecules and how the original usage has evolved to reduce confusionKerber, Robert C. . J. Chem. Educ.2006, 83, 223.

Aromatic Compounds |

Covalent Bonding |

Molecular Properties / Structure |

Nomenclature / Units / Symbols |

Resonance Theory

Are Some Elements More Equal Than Others?Ronald L. RichPresents a new periodic chart with 18 columns but no interruptions of atomic numbers at Lanthanum or Actinum, and no de-emphasis of elements 57-71 or 89-103 by seeming to make footnotes of them. It shows some elements more than once in order to illuminate multiple relationships in chemical behavior. Rich, Ronald L. J. Chem. Educ.2005, 82, 1761.

Atomic Properties / Structure |

Descriptive Chemistry |

Inner Transition Elements |

Main-Group Elements |

Nomenclature / Units / Symbols |

Oxidation State |

Periodicity / Periodic Table |

Transition Elements

Improving Conceptions in Analytical Chemistry: ci Vi = cf VfMargarita Rodríguez-López and Arnaldo Carrasquillo Jr.A common misconception related to analytical chemistry, which may be generalized as the failure to recognize and to account analytically for changes in substance density, is discussed. A cautionary example is made through the use of mass-based units of composition during volumetric dilution. The correct application of the volumetric dilution equation ci Vi = cf Vf is discussed. A quantitative description of the systematic error introduced by incorrect use of the volumetric dilution equation is also specified. Rodríguez-López, Margarita; Carrasquillo, Arnaldo, Jr. J. Chem. Educ.2005, 82, 1327.

Industrial Chemistry |

Nomenclature / Units / Symbols |

Quantitative Analysis |

Solutions / Solvents

Empirical Formulas and the Solid State: A ProposalWilliam B. JensenThis brief article calls attention to the failure of most introductory textbooks to point out explicitly the fact that nonmolecular solids do not have molecular formulas and suggests some practical remedies for improving textbook coverage of this subject. The inadequacies of the terms "empirical formula" and "molecular formula" are also discussed, and the terms "relative compositional formula" and "absolute compositional formula" are proposed as more appropriate alternatives. Jensen, William B. J. Chem. Educ.2004, 81, 1772.

Solid State Chemistry |

Solids |

Stoichiometry |

Nomenclature / Units / Symbols

Etymology as an Aid to Understanding Chemistry ConceptsNittala S. SarmaRecognition of word roots and the pattern of evolution of scientific terms can be helpful in understanding chemistry concepts (gaining knowledge of new concepts represented by related terms). The meaning and significance of various etymological roots, occurring as prefixes and suffixes in technical terms particularly of organic chemistry, are explained in a unified manner in order to show the connection of various concepts vis  vis the terms in currency. The meanings of some special words and many examples are provided. Sarma, Nittala S. J. Chem. Educ.2004, 81, 1437.

Nomenclature / Units / Symbols

The Origin of the Mole ConceptWilliam B. JensenIn response to a reader query, the column traces the origins of the mole concept in chemistry. Jensen, William B. J. Chem. Educ.2004, 81, 1409.

Stoichiometry |

Nomenclature / Units / Symbols

SI for Chemists: A ModificationRobert D. FreemanTo correct my original blunder, I recommend that the name "amount of substance" be replaced by "quant" (rather than posos). The word "quant" is in standard dictionaries and has a single meaning related to boating.Freeman, Robert D. J. Chem. Educ.2004, 81, 802.

Nomenclature / Units / Symbols

SI for Chemists: Another PositionTomislav CvitasI must say that I agree neither with what was said in the original commentary by R. D. Freeman, nor with the letter by P. Karol. Cvitas, Tomislav. J. Chem. Educ.2004, 81, 801.

Reactions (→) vs Equations (=)S. R. LoganA recent chemical kinetics text uses an equals sign for an overall reaction, whereas an arrow is used in each of the reaction steps that are proposed to constitute the mechanism, and for any elementary process. Logan, S. R. J. Chem. Educ.2003, 80, 1258.

Kinetics |

Nomenclature / Units / Symbols |

Reactions |

Mechanisms of Reactions

Organic NomenclatureDavid B. Shaw and Laura R. YindraOrganic Nomenclature is a drill-and-practice exercise in naming organic compounds (using both common and IUPAC names) and identifying structural formulas. It consists of multiple-choice questions where a name or formula is given and the correct formula or name is chosen from a list of five possible answers. Shaw, David B.; Yindra, Laura R. J. Chem. Educ.2003, 80, 1223.

Organic Functional Group Playing Card DeckMichael J. WelshOrganic functional group playing card deck used for review of the name and structure of organic functional groups that can be used to play any game that a normal deck of cards is used for.Welsh, Michael J. J. Chem. Educ.2003, 80, 426.

Nomenclature / Units / Symbols |

Nonmajor Courses |

Enrichment / Review Materials |

Alcohols |

Aldehydes / Ketones |

Alkanes / Cycloalkanes |

Alkenes |

Alkynes |

Amides |

Amines / Ammonium Compounds |

Aromatic Compounds |

Carboxylic Acids |

Esters |

Ethers |

Mechanisms of Reactions |

Synthesis

The Name Game: Learning the Connectivity between the ConceptsMarina C. KoetherGame in which students review words (names of elements and compounds, instrumentation, types of reactions) using an ice-breaker-type activity; each student given a word that they can't see but everyone else can; must learn their name by asking as few yes-no questions as possible.Koether, Marina C. J. Chem. Educ.2003, 80, 421.

Are We Taking Symbolic Language for Granted? Paul Marais and Faan JordaanThis study formed part of a broader investigation into the role of language in teaching and learning chemical equilibrium. Students were tested for their understanding of 25 words and five symbols commonly used in connection with chemical equilibrium. This test showed that most of the students had an inadequate grasp of the meaning of all five symbols. It also showed that, on the average, their understanding of symbols was more problematic than their understanding of words.Marais, Paul; Jordaan, Faan. J. Chem. Educ.2000, 77, 1355.

Classroom Nomenclature Games--BINGOThomas D. CruteThe use of games in the chemistry classroom can provide instruction, feedback, practice, and fun. A modification of a BINGO game to chemical nomenclature and a specific application to alkanes are described. Tips on preparation of materials, and suggested variations including inorganic nomenclature are presented. Crute, Thomas D. J. Chem. Educ.2000, 77, 481.

How to Make Learning Chemical Nomenclature Fun, Exciting, and PalatableJoseph ChimenoOne great challenge that introductory chemistry students have is learning the names of various chemical compounds. To make chemical nomenclature fun, exciting, and palatable, the "Rainbow Wheel" was developed at North Iowa Area Community College. Chimeno, Joseph. J. Chem. Educ.2000, 77, 144.

Nomenclature / Units / Symbols

The Use of Extent of Reaction in Introductory CoursesSebastian G. CanagaratnaThis article discusses the use of the extent of reaction as an alternative to the traditional approach to stoichiometry in first-year chemistry. The method focuses attention on the reaction as a whole rather than on pairs of reagents as in the traditional approach. The balanced equation is used as the unit of change. Canagaratna, Sebastian G. J. Chem. Educ.2000, 77, 52.

Calculating Units with the HP 48G CalculatorMatthew E. MorganThe HP 48G's units function can make simple calculations, such as converting grams to moles, or more complex unit analysis, such as gas law calculations. Examples and calculator keystrokes for both of these examples are included in this article. Morgan, Matthew E. J. Chem. Educ.1999, 76, 631.

Using Games To Teach Chemistry. 2. CHeMoVEr Board GameJeanne V. RussellA board game similar to Sorry or Parcheesi was developed. Students must answer chemistry questions correctly to move their game piece around the board. Card decks contain questions on balancing equations, identifying the types of equations, and predicting products from given reactants. Russell, Jeanne V. J. Chem. Educ.1999, 76, 487.

Stoichiometry |

Nomenclature / Units / Symbols

Using Games to Teach Chemistry. 1. The Old Prof Card GamePhilip L. Granath and Jeanne V. RussellA card game has been developed and used to teach nomenclature of the elements and their symbols in the first laboratory session of General Chemistry. The game both helps the students learn or review the symbols of the elements and is a good "icebreaker" where students learn the names of other students. Granath, Philip L.; Russell, Jeanne V. J. Chem. Educ.1999, 76, 485.

Learning Theories |

Nomenclature / Units / Symbols

CHEMiCALC (4000161) and CHEMiCALC Personal Tutor (4001108), Version 4.0 (by O. Bertrand Ramsay)Scott White and George BodnerCHEMiCALC is a thoughtfully designed software package developed for use by high school and general chemistry students, who will benefit from the personal tutor mode that helps to guide them through unit conversion, empirical formula, molecular weight, reaction stoichiometry, and solution stoichiometry calculations.White, Scott; Bodner, George M. J. Chem. Educ.1999, 76, 34.

A Note on the Term "Chalcogen"William B. JensenIt is argued that the best translation of the term "chalcogen" is "ore former." It is further suggested that the term chalcogenide should be replaced with the term chalcide in order to maintain a parallelism with the terms halogen and halide. Jensen, William B. J. Chem. Educ.1997, 74, 1063.

Nomenclature / Units / Symbols |

Periodicity / Periodic Table |

Descriptive Chemistry

Ionization or Dissociation?Emeric SchultzThe use of the terms Dissociation and Ionization in the teaching of chemistry is discussed. It is suggested that the term dissociation, and what it suggests in terms of ordinary language, is inappropriate when used in certain contexts. Since an alternate and more physically correct term, specifically ionization, is available for these contexts, it is argued that this term be used consistently in these contexts.Schultz, Emeric. J. Chem. Educ.1997, 74, 868.

Interfacing "8088" Computers in the Chemistry LaboratoryJames Goodrich and Bill DurhamThe goal of using such puzzles is to provide a bit of variety to beginning chemistry students and reduce the tedium of memorizing chemical names.Goodrich, James; Durham, Bill. J. Chem. Educ.1996, 73, A130.

Nomenclature / Units / Symbols

Displaying Chemical Formulas in Microsoft ExcelE. Joseph BilloAn Excel macro which automates the entry of subscripts in Excel spreadsheets is described. The macro is assigned to a custom button on Excel's standard toolbar, so that, after typing a text label containing a chemical formula, clicking the button automatically formats the text as a chemical formula.Billo, E. Joseph. J. Chem. Educ.1996, 73, A40.

An Excel 4.0 Add-in Function to Calculate Molecular MassChristian Hauck185. In this paper, a Microsoft Excel 4.0 add-in function is presented, which consists of a parser to interpret molecular formulas and a database containing three values for the atomic masses for every element: the mass number of the most abundant isotope, the mass of the most abundant isotope, and the atomic weight. Hauck, Christian. J. Chem. Educ.1996, 73, 433.

Those Baffling SubscriptsArthur W. Friedel and David P. MaloneyStudy of the difficulties students have in interpreting subscripts correctly and distinguishing atoms from molecules when answering questions and solving problems.Friedel, Arthur W.; Maloney, David P. J. Chem. Educ.1995, 72, 899.

Misusing "molecular"Goldberg, David E.In discussing net ionic equations, the authors of many general chemistry textbooks call the overall equation a "molecular equation", which is misleading at best and incorrect at worst.Goldberg, David E. J. Chem. Educ.1992, 69, 776.

Different Choices (author response)Kemp, H.R.Ronald Rich discusses the use of descriptive units in the problem of calculating the concentration of a 96% sulfuric acid solution of a known density.Kemp, H.R. J. Chem. Educ.1989, 66, 271.

Concerning UnitsStrobel, PierreWadlinger rightly pointed out a number of traps and misunderstandings resulting from an omission of such descriptive units as atom or wave. Here are some more examples, which any chemist dealing with some physics is likely to encounter.Strobel, Pierre J. Chem. Educ.1989, 66, 270.

SI and non-SI units of concentration: A truce?Rich, Ronald L.These authors examine whether a truce could be promoted by filling a chemical gap in the System Internationale with special attention on concentration.Rich, Ronald L. J. Chem. Educ.1986, 63, 784.

Nomenclature / Units / Symbols |

Solutions / Solvents |

Aqueous Solution Chemistry

Find-the-pairsRyan, Jack73. Bits and pieces, 29. A computer game that can help students avoid the drudgery of memorizing such essential items as elemental names and symbols or conversion factors.Ryan, Jack J. Chem. Educ.1986, 63, 626.

Where did that number come from? DeLorenzo, RonaldWith more careful labeling and handling of numbers, instructors can reduce the confusion students sometimes feel when watching problems being solved by the instructor on the board.DeLorenzo, Ronald J. Chem. Educ.1986, 63, 514.

The origin and adoption of the Stock systemKauffman, George B.; Jrgensen, Christian KlixbllThe history and development of the Stock system of inorganic nomenclature.Kauffman, George B.; Jrgensen, Christian Klixbll J. Chem. Educ.1985, 62, 243.

The mole: Questioning format can make a differenceLazonby, John N.; Morris, Jane E.; Waddington, David J.Study of 2,695 high school students that found that it is the piecing together of the individual steps involved in mole calculations that presents the main difficulty for students.Lazonby, John N.; Morris, Jane E.; Waddington, David J. J. Chem. Educ.1985, 62, 60.

Nomenclature / Units / Symbols |

Stoichiometry

A LAP on moles: Teaching an important conceptIhde, JohnThe objective of the Learning Activity Packet on moles include understanding the basic concept of the mole as a chemical unit, knowing the relationships between the mole and the atomic weights in the periodic table, and being able to solve basic conversion problems involving grams, moles, atoms, and molecules. [Debut]Ihde, John J. Chem. Educ.1985, 62, 58.

Stoichiometry |

Nomenclature / Units / Symbols |

Chemometrics |

Atomic Properties / Structure |

Molecular Properties / Structure |

Periodicity / Periodic Table

A new meaning of the terms acid and base hydrolysisMilic, Nikola B.Suggestions for distinguishing between solvation, hydration, and solvolysis, and hydrolysis reactions that produce hydroxo and protonated complexes.Milic, Nikola B. J. Chem. Educ.1984, 61, 1066.

The spilled can of paint Perkins, RobertThe writer describes a problem for students to work out in order to better understand units of conversion.Perkins, Robert J. Chem. Educ.1983, 60, 343.

Nomenclature / Units / Symbols |

Chemometrics

A novel classification of concentration unitsMacCarthy, PatrickConcentration units can be a source of confusion for students. This article presents a treatment on this topic that may help students understand the differences between these units.MacCarthy, Patrick J. Chem. Educ.1983, 60, 187.

Nomenclature / Units / Symbols |

Solutions / Solvents |

Aqueous Solution Chemistry

Numbers in chemical namesFernelius, W. ConardDiscusses the various ways that numbers are used in the formulas and names of chemical compounds.Fernelius, W. Conard J. Chem. Educ.1982, 59, 964.

Notation for order of additionNiewahner, J. H.The notation described here will enable a student to include in the chemical equation an implied statement regarding the order of addition.Niewahner, J. H. J. Chem. Educ.1981, 58, 461.

Compact commentsRhodes, Gale; Goodmanson, DavidA clear derivation of a temperature scale interconversion equation can be carried out by plotting temperatures of one scale against corresponding temperatures of the other.Rhodes, Gale; Goodmanson, David J. Chem. Educ.1980, 57, 506.

Empirical formulasRyan, Dennis P.This question forces one to duplicate the line of reasoning used by Dalton in his initial formulation of atomic weights; it tests for the ability to deduce atomic sizes and to calculate empirical formulas.Ryan, Dennis P. J. Chem. Educ.1979, 56, 528.

The ambit of chemistryVitz, Edward W.Proposal to revise the standard definition of chemistry to one that focusses on atoms and molecules rather than simply matter.Vitz, Edward W. J. Chem. Educ.1979, 56, 327.

The chemical equation. Part I: Simple reactionsKolb, DorisA chemical equation is often misunderstood by students as an "equation" that is used in chemistry. However, a more accurate description is that it is a concise statement describing a chemical reaction expressed in chemical symbolism.Kolb, Doris J. Chem. Educ.1978, 55, 184.

Stoichiometry |

Chemometrics |

Nomenclature / Units / Symbols |

Reactions

What is an element?Kolb, DorisReviews the history of the discovery, naming, and representation of the elements; the development of the spectroscope and the periodic table; radioactive elements and isotopes; allotropes; and the synthesis of future elements.Kolb, Doris J. Chem. Educ.1977, 54, 696.

SI units in physico-chemical calculationsNorris, A. C.This article demonstrates how the adoption of SI units affects some of the more important physico-chemical calculations found at the undergraduate level.Norris, A. C. J. Chem. Educ.1971, 48, 797.

Chemical queries. Especially for introductory chemistry teachersYoung, J. A.; Malik, J. G.; Bolte, John(1) Is the mole a number or a weight? (2) Is there an easy way to locate a compound by volume and page in Beilstein? (3) What are the stages evident in a gas discharge tube as the pressure of the gas and the voltage are changed? - answer by BolteYoung, J. A.; Malik, J. G.; Bolte, John J. Chem. Educ.1968, 45, 718.

The MKS temperature scaleGeorgian, John C.A temperature scale to fit into the MKS system of units is proposed.Georgian, John C. J. Chem. Educ.1966, 43, 414.

Nomenclature / Units / Symbols

Letter to the editorOnwood, D. P.Discusses variations in the usage of the terms "acid" and "base," including Lowry-Bronsted and Lewis systems.Onwood, D. P. J. Chem. Educ.1966, 43, 335.

Acids / Bases |

Lewis Acids / Bases |

Nomenclature / Units / Symbols

Molecules versus molesGuggenheim, E. A.Now that the mass of molecules is known with great accuracy, there is nothing to be gained in continuing to use moles.Guggenheim, E. A. J. Chem. Educ.1966, 43, 250.

Letters to the editorLinde, CharlotteSuggests the term "ionocule" for the opposite of molecule.Linde, Charlotte J. Chem. Educ.1963, 40, 270.

Nomenclature / Units / Symbols

LettersGoldberg, David E.The author suggests using the term "continuous chain" rather than "straight" chain so as to reduce confusion regarding the geometry of carbon chains.Goldberg, David E. J. Chem. Educ.1962, 39, 319.

Molecular Properties / Structure |

Nomenclature / Units / Symbols

Ultramacro and ultramicro science termsde Ment, JackProposes a convenient and consistent set of metric prefixes for very large and very small multiples and sub-multiples.de Ment, Jack J. Chem. Educ.1962, 39, 587.

Nomenclature / Units / Symbols

Editorially SpeakingKieffer, William F.Discussion of the conventions, definitions, and symbols of thermodynamics.Kieffer, William F. J. Chem. Educ.1962, 39, 489.

Nomenclature / Units / Symbols |

Thermodynamics

The carbon-12 scale of atomic massesLabbauf, AbbasExamines the concept of atomic weight and the rise and coexistence of the oxygen and carbon scales of atomic mass.Labbauf, Abbas J. Chem. Educ.1962, 39, 282.

Is there an alternative to pH?Crane, Francis E., Jr.Provides some alternatives to the traditional definition of pH that introductory students may find more intuitive and less confusing.Crane, Francis E., Jr. J. Chem. Educ.1961, 38, 365.

pH |

Acids / Bases |

Nomenclature / Units / Symbols

The mole and related quantitiesGuggenheim, E. A.Examines some of the terminology associated with the mole and expressing amounts of substances.Guggenheim, E. A. J. Chem. Educ.1961, 38, 86.

A molality-molarity paradox?Toby, SidneyThe author points out that there seems no obvious reason why molality could not equal molarity in a solution whose density is less than unity.Toby, Sidney J. Chem. Educ.1959, 36, 230.

Nomenclature of phase transitionMcDonald, James E.Discusses the curious situation in which the terminology of chemistry and physics has only five words to describe the six possible transitions between three states of matter.McDonald, James E. J. Chem. Educ.1958, 35, 205.

Phases / Phase Transitions / Diagrams |

Nomenclature / Units / Symbols

LettersPokras, LewisThe author proposes the term "senacule" as analagous to molecule and to be used to refer to ionic species.Pokras, Lewis J. Chem. Educ.1958, 35, 159.

Gram equivalent weightsMeldrum, William B.The purpose of this paper is to review briefly the subject of equivalent weights and the more directly applicable gram equivalents and to offer a general method by which they may be deduced from chemical equations.Meldrum, William B. J. Chem. Educ.1955, 32, 48.

LettersBrescia, FrankThe author calls for someone to invent another term for the word resonance as applied to the field of molecular structure.Brescia, Frank J. Chem. Educ.1952, 29, 261.

Resonance Theory |

Nomenclature / Units / Symbols |

Molecular Properties / Structure

On accenting observations in chemistryCampbell, J. A.A chemical equations is, for many a student, such a complete abstraction that he would be hard put to describe the actual observations that would be made in a process for which he was supplied the complete equation.Campbell, J. A. J. Chem. Educ.1951, 28, 634.